The weight of onboard hardware remains a major constraint for aircraft. The increasing complexity of electrical, electronic and computer systems gives rise to ever greater amounts of wiring inside airplanes. Thus, hundreds of kilometers of copper cables run through the interior of airplanes, which contributes to increasing the total weight of the onboard hardware. The use of conducting wires that are less dense, made of aluminum for example, does not suffice to solve the problem, given the lengths involved. An effective solution consists in eliminating the maximum of wiring cables and in using autonomous energy sources to power the various components. An exemplary application relates notably to the multitude of sensors located at various places in an airplane. A solution eliminating the wiring then consists in placing an autonomous energy source in proximity to each sensor or to a set of sensors.
In the avionics sector, it is not possible to use batteries because of their overly short lifetime and of their poor temperature performance. One solution consists in using an energy source which recovers the ambient energy for example thermal transducers. It is thus possible to use transducers using the “Seebeck” effect or reverse Pelletier effect. These transducers deliver an electrical potential difference utilizing the difference in temperature between a quantity of water stored inside the transducers and the ambient air, this temperature difference being brought about by the differences in thermal inertia between water and air, or any other temperature gradient. In the case of an airplane, the temperatures of the water and of the air evolve differently in the course of the flight on account of these thermal inertias. Other types of transducers may be used, notably mechanical transducers which may for example utilize the mechanical vibrations of an airplane. These transducers comprise beams of very small size having several branches, the vibrations transmitted to these beams bringing about electrical energy.
These transducers provide voltages or currents which are not stabilized over time. They therefore cannot power electronic components directly. It is known to use voltage or current regulators linked at input to an unstabilized power supply such as a transducer and providing as output a defined voltage, for example 3 volts. Because of the low energy level delivered by the aforementioned transducers, it is necessary to produce regulators which consume a very low energy level, therefore having a very low dropout voltage and very low bias currents, while taking account of the constraints of production, notably as integrated circuits.
An aim of the invention is therefore notably to allow the production of integrated electronic circuits consuming a minimum of current, typically in the nano-power sector, of the order of a few nano-watts.